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- Tu, Zhen, et al.
(författare)
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Digital Twins-Based Automated Pilot for Energy-Efficiency Assessment of Intelligent Transportation Infrastructure
- 2022
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Ingår i: IEEE transactions on intelligent transportation systems (Print). - : Institute of Electrical and Electronics Engineers (IEEE). - 1524-9050 .- 1558-0016. ; 23:11, s. 22320-22330
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Tidskriftsartikel (refereegranskat)abstract
- To realize the great potential of the intelligent transportation infrastructure, the investment in the transportation infrastructure in the intelligent transportation system should be rationally planned. Firstly, the application status of cutting-edge Data Envelopment Analysis (DEA) model in transportation infrastructure efficiency evaluation is analyzed, and based on this, a DEA model of transportation infrastructure efficiency evaluation under Digital Twins technology is established. Secondly, with the transportation infrastructure of 12 prefecture-level cities in Jiangsu Province from 2005 to 2020 as the research object, the Digital Twins DEA model and the traditional Stochastic Frontier Approach (SFA) model are used to estimate the efficiency of transportation infrastructure in 12 cities. Finally, the traffic flow data of a certain road section in Zhenjiang City (J11 City) is simulated and predicted by using the Long Short-term Memory (LSTM) traffic flow prediction model. The results show that the average efficiency of the 12 cities estimated by the DEA model based on the Digital Twins is 0.7083, the average efficiency of the 12 cities estimated by the SFA model is 0.6445, and there are significant differences in the efficiency rankings of the cities. Compared with the actual efficiency, the established Digital Twins DEA model is more reasonable for the calculation of transportation infrastructure efficiency. The results of the LSTM traffic flow prediction model show that the Mean Absolute Error (MAE) of the LSTM model is 24.29, the Root Mean Square Error (RSME) is 0.1186, and the Mean Absolute Perce (MAPE) is 17.78, which are all lower than other models. Compared with other models, the proposed LSTM-based traffic flow prediction model is more accurate in traffic flow prediction. Hence, the research content provides a reference for the investment planning of intelligent transportation system infrastructure.
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- Jiang, Ziwei, et al.
(författare)
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Characterterization of multi-scale nanosilver paste reinforced with SIC particles
- 2020
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Ingår i: China Semiconductor Technology International Conference 2020, CSTIC 2020.
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Konferensbidrag (refereegranskat)abstract
- Nanosilver paste with high operation temperature and low sintering temperature has attracted more and more attention for its promising application in high power devices. In this paper, the thermal properties of multi-scale nanosilver paste composed of nanometer and micrometer silver particles, and Ag-coated SiC particles were investigated. The thermal conductivity of multi-scale nanosilver paste increases with the increasing amount of SiC particles with Ag coating. The maximum value of Vickers hardness for multi-scale nanosilver paste with 0.5 wt.% Ag-coated SiC particles were 24.
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- Li, Miao, et al.
(författare)
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Unmanned aerial vehicle scheduling problem for traffic monitoring
- 2018
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Ingår i: Computers and Industrial Engineering. - : Elsevier BV. - 0360-8352. ; 122, s. 15-23
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Tidskriftsartikel (refereegranskat)abstract
- For more accurate multiple-period real-time monitoring of road traffic, this paper investigates the unmanned aerial vehicle scheduling problem with uncertain demands. A mixed integer programming model is designed for this problem by combining the capacitated arc routing problem with the inventory routing problem. A local branching based solution method is developed to solve the model. A case study which applies this model to the road traffic in Shanghai is performed. In addition, numerical experiments are conducted to validate the effectiveness of the proposed model and the efficiency of the proposed solution method.
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- Lu, Xiuzhen, et al.
(författare)
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Enhanced Mechanical and Thermal Properties of Ag Joints Sintered by Spark Plasma Sintering
- 2022
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Ingår i: Journal of Electronic Materials. - : Springer Science and Business Media LLC. - 1543-186X .- 0361-5235. ; 51:11, s. 6310-6319
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Tidskriftsartikel (refereegranskat)abstract
- Nano-silver paste has been considered to be one of the most promising materials for interconnects of semiconductor devices operating at high temperature. However, its application is limited by conventional sintering methods due to the long dwell time. In this paper, a spark plasma sintering (SPS) technique with a very short sintering time of no more than 5 min was explored for the sintering of nano-silver paste. The effects of sintering conditions including pretreatment time, sintering temperature, dwell time and applied pressure on shear strength and thermal conductivity of the sintered Ag joints were investigated. The shear strength of sintered Ag joints increased as the sintering temperature and applied pressure increased. Robust sintered Ag joints with an average shear strength of 40.18 MPa were obtained by sintering at 300 degrees C for 5 min under a pressure of 3 MPa. The thermal properties were improved by pretreating the nano-silver paste for a shorter time. Thermal conductivity of 41.50 W m(-1) K-1 is obtained for samples pretreated for 25 min and sintered at 250 degrees C for 5 min.
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- Lv, Zhen, et al.
(författare)
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Highly thermally conductive substrate based on graphene film
- 2021
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Ingår i: 2021 23rd European Microelectronics and Packaging Conference and Exhibition, EMPC 2021. ; , s. 195-199
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Konferensbidrag (refereegranskat)abstract
- Heat dissipation has become one of the critical challenges of development for microelectronic products because of the increasing of heat accumulation in the devices. A novel laminated composite with high thermal conductivity was fabricated by hot-pressing using graphene films (GFs) and glass fiber reinforced epoxy resin (GFEP). The effect of GFs with different thicknesses and number of layers on the thermal properties of the composites was investigated. An in-plane thermal conductivity of 141 W · m-1 · K-1 for the laminated composites with GFs and GFEP were obtained. The heat dissipation capability of GFs/GFEP composites is evaluated by infrared thermal imaging technology. The maximum temperature difference between the heating elements on GFs/GFEP composites and GFEP increases with the rise of voltage applied to the heating elements. Moreover, the heat dissipation capability of the composite is enhanced with the increased of the number of layers of GFs. The temperature of the heating element assembled on GFs/GFEP composites is 144.3°C lower than that on GFEP at the same voltage. The results indicate that the GFs/GFEP composites is a promising candidate of substrate material with high heat dissipation capability.
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- Lv, Zhen, et al.
(författare)
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Reduction of thermal resistance of Ag-coated GFs/copper structure using nano-Ag paste as interconnection
- 2022
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 2174:1
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Konferensbidrag (refereegranskat)abstract
- Reduction of the thermal resistance between graphene films (GFs) and substrate is crucial to the application of GFs in thermal management. GFs/copper structures were prepared using nano-Ag paste as interconnection material. The effect of the thickness of nano-Ag paste on thermal resistance of GFs/copper structure was investigated. A thin layer of Ag was coated on GFs by physical vapor deposition (PVD) to further reduce thermal resistance. The thermal resistance of GFs/copper structure using Ag-coated GFs is 5.84% lower than that using raw GFs. The thermal resistance of GFs/copper structure decreases first and then increases with the increase of coating temperature and thickness of Ag layer. The minimum thermal resistance of 1.64 mm2·K·W-1 was gained for GFs/copper structure using GFs coated Ag at 300 ℃ for 60 min.
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